Textile insert for producing a fibrous composite material and fibrous composite material comprising such a textile insert

ABSTRACT

A textile insert consists of two layers (S 1 , S 2 ) composed each of at least one partial layer (S 1a , S 1b , S 2a , S 2b ). These layers are made of woven warp threads (1 1a , 1 1b , 1 2a , 1 2b ) and woof threads (2 1a , 2 1b , 2 2a , 2 2b ). Intermediate layers (Z 1 , Z 2 , Z 3 ) made of standing threads (4 1 , 4 2 , 4 3 ) that extend at least in the longitudinal direction X lie between the partial layers. The whole system is held together by straight or curved connecting threads (3 1 , 3 2 ). A stable textile insert is thus obtained that allows fibrous composite materials to be produced without distortion by a pultrusion process. Sections made of such fibrous composite materials are in addition highly resistant in all three directions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a textile insert for producing a fibrouscomposite material in accordance with the pultrusion or extrusionprocess as well as such a fibrous composite material.

2. Description of the Prior Art

Producing fibrous composite materials, i.e. sections of fiber-reinforcedplastics, in accordance with the pultrusion or extrusion process isknown, as, for instance, from the EP-OS's 0 281 130, 0 382 240 and 0 514718. In them, highly resistant fiber bundles in the form of rovings aredrawn through a matrix material in the form of a resin bath and formedout in a heated nozzle and hardened. These fibrous composite materialsections have high resistance in a longitudinal direction. Theirtransverse resistance, i.e. the resistance transverse to the directionof the longitudinal axis of the fibers, is extremely limited. In orderto eliminate these disadvantages, in addition to the unidirectionalrovings, additional layers in the form of bonded fabric or woven ribbonsare applied, which are to effect a reinforcement in the transversedirection, as evident, for example, from EP-OS 0 285 705. It is alsoknown to deform hose-type fabrics into sections, which are additionallycovered by ribbons, as shown by U.S. Pat. No. 5,132,070. All theprocesses have two essential disadvantages, which have hitherto beenstanding in the way of their large-scale technical application.

Firstly, it is very involved and/or expensive to move such textileinserts, precisely at the right place and without any distortion,through the pultrusion nozzle. While being drawn, the ribbonsadditionally applied for reinforcement are displaced relative to theunidirectional core composed of the rovings and cause rejects.

Secondly, the sections thus produced show, during stress by bending andtorsion moments, little resistance perpendicular to the plane of thetextile layers. This results in delamination, i.e. the rupture of thelayers, and low values for the interlaminar shear strength of thesection.

The object of the invention consists in creating a textile insert bymeans of which fibrous composite materials can be produced in accordancewith the pultrusion or extrusion process and in providing appropriatecomposite materials, which do not have the mentioned disadvantages.

The object is achieved in accordance with the invention by:

a) a textile insert in accordance with as disclosed herein; and

b) the fibrous composite material in accordance with as disclosedherein.

The fundamental techniques in producing woven ribbons, such as, forexample, the production of hoses, auto safety belts, load and lashingstraps and similar, are essentially known, such as, for example, from H.W. Kipp; "Bandwebtechnik" (ribbon weaving technology), VerlagSauerlander, publishers, 1988, Chapter 5: "Bindungen fur Hohl-, Doppel-und Mehrfachgewebe" (connections for hollow, dual and multiple fabrics).For the cost-effective production of such ribbon fabrics, needle-looms,which form a solid fabric edge on both edges of the fabric, areparticularly suitable.

As a result of the multilayered build-up, in which, moreover, all thelayers are connected to each other at least via partial areas, and as aresult of the arrangement of standing threads running in a horizontaldirection, the textile insert has a mechanical resistance, which allowsthe distortion-free processing of the textile insert in the pultrusionor extrusion process. Moreover, additional reinforcing supports are nolonger required. Because additionally, the textile insert can beprefabricated, coiled and held in intermediate storage as a semifinishedproduct in continuous form, the pultrusion and/or extrusion process isalso simplified because the involved and/or expensive and error-proneassembly of threads and covering layers hitherto common becomessuperfluous.

The textile insert thus consists of a mixture of genuine fabric layerswith intersecting warp and weft threads and mats of the incorporatedstanding threads. As a result, a compact slip-resistant build-up isachieved, which can be well manipulated and processed. Mats alone arenot slip-resistant and are hard to store, manipulate and processfurther. As a result of the build-up of the textile insert in accordancewith the invention, the textile inserts as well as the later fibrouscomposite materials can be produced almost endlessly and, therefore,also in a particularly economical manner.

From the combination of fabric and mat result, in a fibrous compositematerial, particularly good resistance characteristics so that such afibrous composite material can, even during rupture, absorb great forcesin all three directions, thus, in addition, particularly avoiding therisk of delamination. Mats alone do not have any resistance in atransverse direction. Fabrics or other textile structure types(braiding, knits, wrappings and similar) alone produce insufficientresistances or excessive elongation.

Advantageous enhancements of the textile inserts are described in Claims2 through 10.

Particularly advantageous enhancements of the textile inserts aredescribed in the Claims 2 and 3, which can be processed into preferredstable fiber composite materials. Particularly advantageous, for thispurpose, is an enhancement in accordance with Claim 4.

The threads can, in accordance with Claim 5, consist of variousmaterials. Advantageous, however, is an enhancement in accordance withClaim 6. Materials that are suitable are, for example, glass, aramid orcarbon fibers. Expedient is an enhancement in accordance with Claim 7 sothat such a textile insert can be processed directly, without anypreceding immersion phase, into a matrix material using the pultrusionor extrusion process.

A particularly advantageous enhancement of the textile insert isdescribed in Claim 8 which allows a particularly versatile shaping ofthe section of the fibrous composite material to be produced. Theembodiment in accordance with Claim 9 allows producing fibrous compositematerials having a hollow section.

Sample embodiments of the object of the invention are described in moredetail hereinafter based on the drawings, the following being presented:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a a textile insert with straight connecting threads, in a cutoutand in a cross section;

FIG. 1b a textile insert in analogy to FIG. 1 a but with the connectingthreads undulated;

FIG. 2 a textile insert of two layers, which are connected to each otherby the longitudinal edges, too, in a transverse view and in a schematicrepresentation;

FIG. 3 a fibrous composite material from a textile insert in accordancewith FIG. 2 in a transverse view;

FIG. 4 a textile insert of two layers, the outer longitudinal edges ofwhich are not connected to each other, in a transverse view and in aschematic representation;

FIG. 5 a fibrous composite material of a textile insert in accordancewith FIG. 4; and

FIG. 6 fibrous composite materials of various cross section shapes.

FIG. 1 shows the build-up of a multilayered textile insert with threadorientations in the three main directions--longitudinal direction X=warpdirection, transverse direction Y=weft direction, and Z=connectiondirection. The textile insert comprises two layers S₁ and S₂, each ofwhich comprises at least one partial layer but which, in the presentexample, is built up of partial layers S_(1a), S_(1b), S_(2a), S_(2b).Each partial layer comprises, warp threads 1₁, 1₂ running inlongitudinal direction X and weft threads 2₁, 2₂ running in transversedirection Y which are interwoven. Between the two layers S₁ and S₂, onthe one hand, and the partial layers S_(1a), S_(1b) and S_(2a), S_(2b)on the other hand, in each case, intermediate layers Z₁, Z₂, Z₃ arearranged, which are formed by straight standing threads 4₁, 4₂, 4₃running in longitudinal direction X and by standing threads 6₁, 6₂, 6₃running in transverse direction Y. The individual layers can beconnected to each other by straight connecting threads 3₁ (FIG. 1a)and/or connecting threads 3₂ (FIG. 1b) that are undulated. Depending onthe requirements for the fibrous composite material, not all the threadsystems will be needed; in particular, the portion of the standingthreads 4₁, 4₂, 4₃ running in the direction of the warp can be increasedat the expense of other thread systems, for example that of the standingthreads 6₁, 6₂, or 6₃ that run in transverse direction Y. The resistancecan also be influenced by an appropriate selection of the pretension ofthe standing threads. This results in greater resistance and lesselongation in longitudinal direction X. The textile insert and, as aconsequence, also the fibrous composite material produced from it canthus be optimally adjusted to a specific application.

FIG. 2 shows a textile insert composed of the two main layers S₁ and S₂,which are composed of, for example, of the partial layers S_(1a) andS_(1b) as well as S_(2a) and S_(2b), the partial layers being connectedby means of connecting threads 3₃ in connection direction Z. The twolayers S₁, S₂ are connected, in a center area A by means of connectingthreads 3₁ and by the edges C by means of the connecting threads 3₄.From such a textile insert, a dual-T-section in accordance with FIG. 3can, for example, be produced, with a bridge 7 from center section A andtraversing legs 8, 9 of thickness D, which corresponds to thickness D ofthe textile insert, and width F, which essentially corresponds to thelength of unconnected Section B of the layers S₁ and S₂.

FIG. 4 shows a textile insert, again composed of the two layers S₁ andS₂ with the partial layers S_(1a), S_(1b) and S_(2a), S_(2b), which arenot connected to each other by their longitudinal edges C₁. The fibrouscomposite material section produced from this textile insert ispresented in FIG. 5. In this case, the dual T-shaped section again has acenter bridge 7 of thickness D, which corresponds to thickness D of thetextile insert. The length of bridge A corresponds to the connectedcentral partial section A of the textile insert. The traversing legs 8₁and 9₁ have a width F₁, which corresponds approximately to double thelength of the unconnected section B of the layers. Thickness D₁ of thesebridges is equal to half of thickness D of the textile insert.

FIG. 6 shows examples of different section shapes, in which the fibrouscomposite material can be produced.

The thickness of the textile insert and, as a result, the wall thicknessof the fibrous composite material section produced from it is affectedby the number of the layers as well as by the number of the threadsystems and, in each case, the thread thickness and thread densitywithin each thread system. In a four-layer fabric of glass fibers of athickness of 408 tex, with a weft density of 3×8 wefts/cm, with a threaddensity of the warp thread system of 80 threads/cm, with a threaddensity of the connecting thread system of 4.5 threads/cm and a threaddensity of the standing thread system of 80 threads/cm, a thickness D ofapprox. 7 mm or a leg thickness D₁ of 3.5 mm results, measured on thefinished fibrous composite material. The fabric thickness prior toproducing the section is approx. 10% greater.

REFERENCE NUMBER LIST

A Partial area connected

B Partial area not connected

C Longitudinal edges connected

C₁ Longitudinal edges unattached

D Thickness of layer

D₁ Thickness of partial layer

F Width of leg

F₁ Width of leg

S₁ Layer

S_(1a) Partial layer

S_(1b) Partial layer

S₂ Layer

S_(2a) Partial layer

S_(2b) Partial layer

X Longitudinal direction (warp thread run)

Y Transverse direction (weft thread run)

Z Connection direction (connecting thread run)

1₁ Warp

1₂ Warp

2₁ Weft

2₂ Weft

3₁ Connecting thread in connection direction Z

3₂ Connecting thread in connection direction Z

3₃ Connecting thread in connection direction Z

3₄ Connecting thread in connection direction Z

4₁ Standing thread in longitudinal direction X

4₂ Standing thread in longitudinal direction X

4₃ Standing thread in longitudinal direction X

6₁ Standing thread in transverse direction X

6₂ Standing thread in transverse direction Y

6₃ Standing thread in transverse direction Y

7 Bridge

8 Leg

8₁ Leg

9 Leg

9₁ Leg

We claim:
 1. A band-shaped textile insert for producing a fibercomposite material according to the pultrusion or extrusion processincluding at least two woven layers, each layer comprising interwovenwarp threads running in a longitudinal direction and weft threadsrunning in a transverse direction, said two woven layers being onlyconnected to each other across one or more areas of their cross sectionby means of connecting threads oriented in a connection direction andfurther comprising a system of standing threads running in alongitudinal direction, the two woven layers being separable from eachother and deformable at areas that are not connected to each other. 2.Textile insert in accordance with claim 1, wherein each layer is formedof at least one partial layer arranged parallel to the partial layer ofthe other layer and comprising interwoven threads interconnected bymeans of said connecting threads in said connection direction. 3.Textile insert in accordance with claim 2, wherein at least between saidindividual layers and said partial layers, an intermediate layer isarranged comprising the standing threads running in a longitudinaldirection and standing threads running in a transverse direction. 4.Textile insert in accordance with claim 3, characterized by the factthat said standing threads are substantially straight.
 5. Textile insertin accordance with claim 1 wherein the threads of the individual threadsystems consist of different materials.
 6. Textile insert in accordancewith claim 1 wherein the threads of all thread systems consist of thesame highly resistant material.
 7. Textile insert in accordance withclaim 1 wherein the threads of at least one of the thread systems areprovided with a matrix material.
 8. Textile insert in accordance withclaim 1 wherein each of said layers presents an outer longitudinal edgeand adjacent layers are not connected to each other by their respectiveouter longitudinal edges.
 9. Textile insert in accordance with claim 1wherein each of said layers presents an outer longitudinal edge andadjacent layers are connected to each other at their respective outerlongitudinal edges by means of a connecting thread oriented in saidconnection direction.
 10. Textile insert in accordance with claim 1wherein said insert is produced on a needle ribbon loom.
 11. Fibrouscomposite material, which comprises, in a matrix material, a textileinsert in accordance with claim
 1. 12. A textile insert in accordancewith claim 6, wherein said highly resistant material is glass.
 13. Atextile insert as set forth in claim 7, wherein said matrix material isa thermoplastic synthetic resin.